The overall goal of this proposal is to obtain prevalence figures of Raynaud phenomenon (RP) in the general population based on objective criteria, to define the risk factors associated with a serious outcome of RP, and to study the evolution of RP and associated findings during a follow-up period. The project will consist of 5 interrelated studies: 1) questionnaire data on cold sensitivity from population survey, 2) field examinations to objectively determine the presence of RP, 3) clinical evaluation and experimental studies of the survey subjects suffering from RP and their controls at the Arthritis Center in Charleston, SC, 40 case-control study of survey subjects compared to clinic patients belonging to the same spectrum of RP - connective tissue disease (CTD) continuum and 5) prospective cohort study of a subgroup of survey with RP and suspected early CTD and their matched idiopathic RP (IRP) controls. The following experimental variables will be studied: digital blood flow, digital blood pressure, capillary morphology, capillary blood flow, capillary blood pressure, rheological factors, such as platelet aggregation and Beta-thromboglobulin levels, and antinuclear antibodies. The capillary abnormalities of scleroderma (SD)-type will also be used as predictors in the prospective study. The results of this study will provide a basis that we present lack for estimating the risk of CTD in patients presenting with RP as well as the probability that they may have a benign IRP. In addition, we hope to determine the relative proportions of patients with a mild, slowly progressing form of SD and those with classical SD by comparing our survey figures of suspected early SD with previously reported prevalence rates of classical SD. Moreover, such early detection of CTD will improve our understanding of early preclinical pathogenetic mechanisms in these disorders.